The present invention relates to the preparation of shrimp so as to leave the tail of the shrimp attached to the flesh body of the shrimp from which the shell is removed.
Cleaned shrimp consisting of flesh bodies of shrimp to which the shrimp tails remain attached and from which the sand veins and main portions of the shrimp shells have been removed have been referred to as cleaned "tail-on" shrimp.
The production of cleaned "tail-on" shrimp is complicated by the fact that the flesh bodies of raw shrimp have only very limited structural strength, the strength of each flesh body being weakest at the juncture of the shrimp tail with the flesh body. Moreover, this weak portion of the flesh body, which must be relied on to hold the tail attached to the flesh body, is vulnerable to being damaged as an incident to separation of the shrimp tail from the main portion of the shrimp shell in the production of "tail-on" shrimp. As a consequence, the tail of each shrimp is subject to being pulled loose from the flesh body of the shrimp, leaving the body tailless or with the tail so insecurely attached that the purpose of having "tail-on" shrimp is effectively diminished.
Machines have been designed to include shrimp tail breaker assemblies for separating the shrimp tail from the main shell of the shrimp without fracturing the shrimp flesh or meat. One method of breaking the shrimp tail to provide a tail-on shrimp is described in U.S. Pat. Nos. 3,247,542 and 3,277,517. The apparatus shown in these patents stretches the shell longitudinally with the shrimp tail being pulled relative to the stationary shrimp body shell. See, for example, U.S. Pat. No. 3,247,542, column 5, line 46 to column 6, line 61.
To carry out the shrimp tail breaking operation, tail breaker assemblies are employed to cause two pairs of clutch assemblies to contact the shrimp shell and tail section in a desired sequence determined by selected cam paths whereby the shrimp tail is fractured or separated from the shrimp shell without damaging or fracturing the shrimp flesh.
While shrimp cleaning machines having tail breaker assemblies have been found to be satisfactory for producing tail-on shrimp, several shortcomings exist with these machines. Initially, when shrimp of different size are processed through the machines, the tail breaker cam assemblies employed at the shrimp tail breaking station must be adjusted manually to accommodate various size shrimp. The reason for the adjustment is that both the shell and meat of shrimp are relatively fragile and, it has been found, they will be damaged or crushed excessively by the clutch assemblies in the event the tail breaker cam assemblies are not properly adjusted for various size shrimp. Unfortunately, it has been found that, in some instances, an operator will forget to make the necessary adjustment to accommodate a particular size shrimp or the adjustment will be made incorrectly whereby the shrimp is damaged or destroyed.
Another problem centers on the movement of the two pairs of clutch assemblies which contact the shrimp body and tail in a tail breaking operation. One pair of clutch assemblies is moved or pivoted a certain distance or "stroke" relative to the other pair of clutch assemblies whereby the shrimp tail is pulled relative to the stationary body shell to achieve the desired fracture or separation. This stroke is critical because too much stroke will over-stretch a small shrimp and damage it while too little stroke will not reliably separate the tail shell joint from the main shell on a large shrimp. Shrimp peeling machines presently available have employed manually adjustable tail breaker cams which serve as a compromise between the two stroke extremes whereby the stroke is constant and limited to a relatively small amount to avoid excessive damage to the shrimp.
What is desired is a shrimp peeling machine which includes a tail breaker means which permits a shrimp shell tail to be separated or fractured from the main body without fracturing the shrimp flesh with the tail breaker means automatically accommodating various size shrimp and delivering the particular stroke required for shrimp of different sizes.